The Great Epic of the Bhārata dynasty 6.41.89

6.41.89

atha sainyasya madhye tu prākrośatpāṇḍavāgrajaḥ |
yo'smānvṛṇoti tadahaṃ varaye sāhyakāraṇāt || 89 ||

"Karna said, 'I will not do anything that is disagreeable to Dhritarashtra's son, O Kesava. Devoted to Duryodhana's good, know that I have cast off my life (for him).--Hearing these words (of Karna), Krishna ceased, O Bharata, and reunited himself with the sons of Pandu headed by Yudhishthira. Then amid all the warriors the eldest son of Pandu, loudly exclaimed,--He who will choose us, him we shall choose for our ally!--Casting his eyes then upon them, Yuyutsu said these words, with a cheerful heart, unto Kunti's son king Yudhishthira the Just,--I will fight under thee in battle, for the sake of you all, with the sons of Dhritarashtra, if, O king, thou wilt accept me, sinless one.'